Vulnerability-Lookup

FKIE_CVE-2026-64399

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-07-27 05:16

Severity

9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE The FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the destination file's data via vfs_clone_file_range() with neither the share-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle fp->daccess check that the other write-bearing arms carry. A client can overwrite destination data on a read-only share, or from a handle opened with only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp). FILE_WRITE_ATTRIBUTES-only destination handle overwrote the file's data via the clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix; require FILE_WRITE_DATA since this writes data.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5a
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5df
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfe

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bf460ad5958d506492de4524a656439da3f99c51",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            },
            {
              "lessThan": "620d133d469295ee7c017ca6aafac335f65c4a5a",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            },
            {
              "lessThan": "9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            },
            {
              "lessThan": "baae7b39673ec21073a25e3d14f8feaada01d5df",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            },
            {
              "lessThan": "c917e4522d251071dde9871b9142d8ea1186ebfe",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            },
            {
              "lessThan": "388e4139db27a9e3612c9d356b826f5b1ff6a9e3",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE\n\nThe FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the\ndestination file\u0027s data via vfs_clone_file_range() with neither the\nshare-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle\nfp-\u003edaccess check that the other write-bearing arms carry. A client can\noverwrite destination data on a read-only share, or from a handle opened\nwith only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp).\nFILE_WRITE_ATTRIBUTES-only destination handle overwrote the file\u0027s data via\nthe clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix;\nrequire FILE_WRITE_DATA since this writes data."
    }
  ],
  "id": "CVE-2026-64399",
  "lastModified": "2026-07-27T05:16:47.010",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-25T10:17:23.397",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5df"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfe"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-64399 (GCVE-0-2026-64399)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-08-05 12:41

Title

ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE

Summary

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux

References

6 references

URL	Tags
https://git.kernel.org/stable/c/bf460ad5958d50649…
https://git.kernel.org/stable/c/620d133d469295ee7…
https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b…
https://git.kernel.org/stable/c/baae7b39673ec2107…
https://git.kernel.org/stable/c/c917e4522d251071d…
https://git.kernel.org/stable/c/388e4139db27a9e36…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < bf460ad5958d506492de4524a656439da3f99c51 (git) Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < 620d133d469295ee7c017ca6aafac335f65c4a5a (git) Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < 9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6 (git) Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < baae7b39673ec21073a25e3d14f8feaada01d5df (git) Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < c917e4522d251071dde9871b9142d8ea1186ebfe (git) Affected: eb817368f50c1cbe1bd07044124aad7db6330e3a , < 388e4139db27a9e3612c9d356b826f5b1ff6a9e3 (git)
Linux	Linux	Affected: 5.15 Unaffected: 0 , < 5.15 (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.96 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bf460ad5958d506492de4524a656439da3f99c51",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            },
            {
              "lessThan": "620d133d469295ee7c017ca6aafac335f65c4a5a",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            },
            {
              "lessThan": "9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            },
            {
              "lessThan": "baae7b39673ec21073a25e3d14f8feaada01d5df",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            },
            {
              "lessThan": "c917e4522d251071dde9871b9142d8ea1186ebfe",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            },
            {
              "lessThan": "388e4139db27a9e3612c9d356b826f5b1ff6a9e3",
              "status": "affected",
              "version": "eb817368f50c1cbe1bd07044124aad7db6330e3a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.96",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.39",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2-rc1",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE\n\nThe FSCTL_DUPLICATE_EXTENTS_TO_FILE arm of smb2_ioctl() overwrites the\ndestination file\u0027s data via vfs_clone_file_range() with neither the\nshare-level KSMBD_TREE_CONN_FLAG_WRITABLE check nor a per-handle\nfp-\u003edaccess check that the other write-bearing arms carry. A client can\noverwrite destination data on a read-only share, or from a handle opened\nwith only FILE_WRITE_ATTRIBUTES (which still yields an FMODE_WRITE filp).\nFILE_WRITE_ATTRIBUTES-only destination handle overwrote the file\u0027s data via\nthe clone. Add both checks, matching the FSCTL_SET_SPARSE permission fix;\nrequire FILE_WRITE_DATA since this writes data."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - An attacker reaches smb2_ioctl() remotely through ksmbd\u2019s SMB service on TCP port 445.\nAC:L - The attacker directly controls both file handles, offsets, length, and request timing; no race or uncontrollable condition is required on a clone-capable filesystem.\nPR:N - A passwordless guest session on a guest-enabled share can obtain the required session, tree connection, and file handles without credentials.\nUI:N - The attacker independently negotiates the SMB session, opens the files, and submits the malicious IOCTL without victim action.\nS:U - The unauthorized file modification and any resulting code execution remain within the host kernel and services governed by the same security authority.\nC:H - In a plausible share containing service-loaded code or configuration, attacker-controlled extent replacement can yield code execution and consequent access to sensitive data.\nI:H - The attacker can overwrite arbitrary destination ranges with chosen source data despite a read-only share or a handle lacking FILE_WRITE_DATA.\nA:H - Repeated or complete corruption of critical files, databases, executables, or service configuration can cause a persistent loss of the affected system or service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:41:37.295Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/bf460ad5958d506492de4524a656439da3f99c51"
        },
        {
          "url": "https://git.kernel.org/stable/c/620d133d469295ee7c017ca6aafac335f65c4a5a"
        },
        {
          "url": "https://git.kernel.org/stable/c/9b9cf7e65cbeaae1b6636144bacee611cdd7a5d6"
        },
        {
          "url": "https://git.kernel.org/stable/c/baae7b39673ec21073a25e3d14f8feaada01d5df"
        },
        {
          "url": "https://git.kernel.org/stable/c/c917e4522d251071dde9871b9142d8ea1186ebfe"
        },
        {
          "url": "https://git.kernel.org/stable/c/388e4139db27a9e3612c9d356b826f5b1ff6a9e3"
        }
      ],
      "title": "ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64399",
    "datePublished": "2026-07-25T08:50:42.925Z",
    "dateReserved": "2026-07-19T15:36:31.785Z",
    "dateUpdated": "2026-08-05T12:41:37.295Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

FKIE_CVE-2026-64399

CVE-2026-64399 (GCVE-0-2026-64399)

Tags

Sightings

Nomenclature